학술논문
Radio observations of the merging galaxy cluster system Abell 3391-Abell 3395
Document Type
Working Paper
Author
Brüggen, M.; Reiprich, T. H.; Bulbul, E.; Koribalski, B. S.; Andernach, H.; Rudnick, L.; Hoang, D. N.; Wilber, A. G.; Duchesne, S. W.; Veronica, A.; Pacaud, F.; Hopkins, A. M.; Norris, R. P.; Johnston-Hollitt, M.; Brown, M. J. I.; Bonafede, A.; Brunetti, G.; Collier, J. D.; Sanders, J. S.; Vardoulaki, E.; Venturi, T.; Kapinska, A. D.; Marvil, J.
Source
Subject
Language
Abstract
The pre-merging system of galaxy clusters Abell 3391-Abell 3395 located at a mean redshift of 0.053 has been observed at 1 GHz in an ASKAP/EMU Early Science observation as well as in X-rays with eROSITA. The projected separation of the X-ray peaks of the two clusters is $\sim$50$'$ or $\sim$ 3.1 Mpc. Here we present an inventory of interesting radio sources in this field around this cluster merger. While the eROSITA observations provide clear indications of a bridge of thermal gas between the clusters, neither ASKAP nor MWA observations show any diffuse radio emission coinciding with the X-ray bridge. We derive an upper limit on the radio emissivity in the bridge region of $\langle J \rangle_{1\,{\rm GHz}}< 1.2 \times 10^{-44} {\rm W}\, {\rm Hz}^{-1} {\rm m}^{-3}$. A non-detection of diffuse radio emission in the X-ray bridge between these two clusters has implications for particle-acceleration mechanisms in cosmological large-scale structure. We also report extended or otherwise noteworthy radio sources in the 30 deg$^2$ field around Abell 3391-Abell 3395. We identified 20 Giant Radio Galaxies, plus 7 candidates, with linear projected sizes greater than 1 Mpc. The sky density of field radio galaxies with largest linear sizes of $>0.7$ Mpc is $\approx 1.7$ deg$^{-2}$, three times higher than previously reported. We find no evidence for a cosmological evolution of the population of Giant Radio Galaxies. Moreover, we find seven candidates for cluster radio relics and radio halos.
Comment: Astronomy & Astrophysics, in press
Comment: Astronomy & Astrophysics, in press